The presence of calcium oxalate monohydrate crystal growth inhibitors (kidney stone inhibitors) in human urine, human embryonic kidney tissue culture medium, and rat kidneys has been established in our laboratory. The following plans will be carried out to elucidate further properties and mechanism of action of calcium oxalate monohydrate crystal growth inhibitors isolated from human urine and rat kidney. A. Human urinary inhibitors. (1) Characterization.--Urinary inhibitors purified from children, normal adults and kidney stone patients will be characterized by their chemical compositions (amino acid and carbohydrate compositions, phosphate, sulfate, etc.), and physico-chemical properties (mol. wt., surface properties, viscosity, mobility in electric field, kinetic analysis of calcium oxalate monohydrate crystal growth inhibition). (2) Primary sequence of protein and carbohydrate.--Primary sequence of purified urinary inhibitor will be determined by using Beckman sequencer. Carbohydrate sequence will be elucidated by chemical and enzymatic hydrolyses. (3) Synthesis of the inhibitor or model peptides. B. Rat kidney inhibitor. (1) Characterization of inhibitors purified from normal and calcium oxalate stone induced rat kidneys.--Calcium oxalate monohydrate crystal growth inhibitors will be purified from kidneys of normal and kidney stone induced rats, and investigate the difference of both inhibitors. (2) Immunochemical tests and localization of inhibitor in tissue.--Using the inhibitor isolated from normal rat kidneys will be injected into rabbits for production of antibody, then use the formed antibody for immunochemical tests.